//
//  MIT License
//
//  Copyright (c) 2014 Bob McCune http://bobmccune.com/
//  Copyright (c) 2014 TapHarmonic, LLC http://tapharmonic.com/
//
//  Permission is hereby granted, free of charge, to any person obtaining a copy
//  of this software and associated documentation files (the "Software"), to deal
//  in the Software without restriction, including without limitation the rights
//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//  copies of the Software, and to permit persons to whom the Software is
//  furnished to do so, subject to the following conditions:
//
//  The above copyright notice and this permission notice shall be included in
//  all copies or substantial portions of the Software.
//
//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
//  THE SOFTWARE.
//

#import "THFrameRateCalculator.h"
#import <AVFoundation/AVFoundation.h>

@interface THFrameRateCalculator ()
@property (strong, nonatomic) NSMutableArray *previousSecondTimestamps;
@end

@implementation THFrameRateCalculator

- (instancetype)init {
    self = [super init];
    if (self) {
        _previousSecondTimestamps = [NSMutableArray array];
    }
    return self;
}

- (void)calculateFramerateAtTimestamp:(CMTime)timestamp {
    NSValue *timestampValue = [NSValue valueWithCMTime:timestamp];
	[self.previousSecondTimestamps addObject:timestampValue];

	CMTime oneSecond = CMTimeMake(1, 1);
	CMTime oneSecondAgo = CMTimeSubtract(timestamp, oneSecond);

    CMTime time = [[self.previousSecondTimestamps firstObject] CMTimeValue];
	while(CMTIME_COMPARE_INLINE(time, <, oneSecondAgo)) {
		[self.previousSecondTimestamps removeObjectAtIndex:0];
        time = [[self.previousSecondTimestamps firstObject] CMTimeValue];
    }

	Float64 newRate = [self.previousSecondTimestamps count];
    self.frameRate = (self.frameRate + newRate) / 2;
}

@end